Loxosceles Sphingomyelinase Induces Complement-Dependent Dermonecrosis, Neutrophil Infiltration, and Endogenous Gelatinase Expression

• Published in: Journal of investigative dermatology Vol. 124; no. 4; pp. 725 - 731
• Main Authors: Tambourgi, Denise V., Paixão-Cavalcante, Danielle, Gonçalves de Andrade, Rute M., Fernandes-Pedrosa, Matheus de F., Magnoli, Fábio C., Paul Morgan, B., van den Berg, Carmen W.
• Format: Journal Article
• Language: English
• Published: Danvers, MA Elsevier Inc 01.04.2005; Nature Publishing; Elsevier Limited
• Subjects: Animals; Araneae; Biological and medical sciences; complement; Complement System Proteins - drug effects; Complement System Proteins - immunology; Dermatology; dermonecrosis; Erythrocytes - immunology; Fibroblasts - enzymology; Fibroblasts - pathology; Hemolysis; Loxosceles; Loxosceles intermedia; Loxosceles spider venom; Male; Matrix Metalloproteinase 2 - metabolism; Matrix Metalloproteinase 9 - metabolism; Medical sciences; MMP-2; MMP-9; Necrosis; neutrophils; Neutrophils - enzymology; Neutrophils - immunology; Neutrophils - pathology; Rabbits; Sheep; Skin Diseases - chemically induced; Skin Diseases - immunology; Skin Diseases - pathology; Sphingomyelin Phosphodiesterase - toxicity; sphingomyelinase; Spider Bites - immunology; Spider Bites - metabolism; Spider Bites - pathology; Spider Venoms - toxicity; Spiders; Loxosceles spider venom; MMP-2; sphingomyelinase; dermonecrosis; complement; MMP-9; neutrophils; Envenomation; Enzyme; Dermatology; Granulocyte; Rabbit; Metalloendopeptidases; Complement; complement/dermonecrosis/Loxosceles spider venom/MMP-2/MMP-9/neutrophils/sphingomyelinase; Lagomorpha; Gelatinase B; Gelatinase A; Peptidases; Vertebrata; Arachnida; Mammalia; Endogenous; Arthropoda; Animal; Venom; Spider; Hydrolases; Infiltration; Neutrophil; Invertebrata
• ISSN: 0022-202X; 1523-1747
• DOI: 10.1111/j.0022-202X.2005.23654.x

Envenomation by the spider Loxosceles can result in dermonecrosis and severe ulceration. Our aim was to investigate the role of the complement system and of the endogenous metalloproteinases in the initiation of the pathology of dermonecrosis. Histological analysis of skin of rabbits injected with Loxosceles intermedia venom and purified or recombinant sphingomyelinases showed a large influx of neutrophils, concomitant with dissociation of the collagenous fibers in the dermis. Decomplementation, using cobra venom factor, largely prevented the influx of neutrophils, while influx of neutrophils was also reduced in genetically C6-deficient rabbits, suggesting roles for both C5a and the membrane attack complex in the induction of dermonecrosis. However, C-depletion and C6 deficiency did not prevent the haemorrhage and the collagen injury. Zymography analysis of skin extracts showed the induction of expression of the endogenous gelatinase MMP-9 in the skin of envenomated animals. Rabbit neutrophils contained high levels of MMP-9, expression of which was further increased after incubation with venom, suggesting that these cells may be a source of the MMP-9 found in the skin of envenomated animals. Furthermore, skin fibroblasts also secreted MMP-9 and MMP-2 upon incubation with venom, suggesting that locally produced MMPs can also contribute to proteolytic tissue destruction.